Actually, flash heal is quite efficient when you use the glyph. The only time I ever used Gheal as holy was on Patch, it's too slow other wise. Maybe that'll change in 3.1.
You should be using Glyphs of Flash heal, CoH and a 3rd major of your choice. And one of your minor glyphs should be the shadow fiend glyph. I also recommend the levitate glyph to save a bag slot (no more feathers).
Honestly, I would rework your spec a bit. You're missing a ton of bonus healing on your two main spells by not filling out Empowered Healing. Same for Divine Providence (which is actually nice for 7 second PoM CDs if you have 2 piece T7, especially on Sapphiron).
And as everyone else has said, enchant your gear. Spellpower to gloves, bracers & weapon are cheap as is speed to cloak. Get out and do the Hodir dailies for the shoulder enchant; you'll make more money doing the quests than you'll spend on shoulder enchants anyhow.